Inclusion compounds of N,N,N′,N′-tetraisopropylfumaride with isomers of methyl phenol and water

The crystal structures and thermal analyses of the host compound, N,N,N,N-tetraisopropylfumaride, witho-cresol,m-cresol and water are reported and compared to that of thep-cresol complex previously reported in an attempt to elucidate the reasons for host selectivity.     

Conditional functional equations and orthogonal additivity

Summary Some examples of classes of conditional equations coming from information theory, geometry and from the social and behavioral sciences are presented. Then the classical case of the Cauchy equation on a restricted domain is extensively discussed. Some results concerning the extension of local homomorphisms and the implication -additivity implies global additivity are illustrated. Problems concerning the equations[cf(x + y) – af(x) – bf(y) – d][f(x + y) – f(x – f(y)] = 0[g(x + y) – g(x) – g(y)][f(x + y) – f(x) – f(y)] = 0f(x + y) – f(x) – f(y) V (a suitable subset of the range) are presented.The consideration of the conditional Cauchy equation is subsequently focused on the case when it makes sense to interpret as a binary relation (orthogonality):f: (X, +, ) (Y, +);f(x + z) = f(x) + f(z) (x, z Z; x z). A brief sketch on solutions under regularity conditions is given. It is then shown that all regularity conditions can be removed. Finally, several applications (also to physics and to the actuarial sciences) are discussed. In all these cases the attention is focused on open problems and possible extensions of previous results.     

The theoretical apparatus of semantic realism: A new language for classical and quantum physics

The standard interpretation of quantum physics (QP) and some recent generalizations of this theory rest on the adoption of a rerificationist theory of truth and meaning, while most proposals for modifying and interpreting QP in a realistic way attribute an ontological status to theoretical physical entities (ontological realism). Both terms of this dichotomy are criticizable, and many quantum paradoxes can be attributed to it. We discuss a new viewpoint in this paper (semantic realism, or briefly SR), which applies both to classical physics (CP) and to QP. and is characterized by the attempt of giving up verificationism without adopting ontological realism. As a first step, we construct a formalized observative language L endowed with a correspondence truth theory. Then, we state a set of axioms by means of L which hold both in CP and in QP. and construct a further language L_v which can express bothtestable andtheoretical properties of a given physical system. The concepts ofmeaning andtestability do not collapse in L and L_e hence we can distinguish between semantic and pragmatic compatibility of physical properties and define the concepts of testability and conjoint testability of statements of L and L_e. In this context a new metatheoretical principle (MGP) is stated, which limits the validity of empirical physical laws. By applying SR (in particular. MGP) to QP, one can interpret quantum logic as a theory of testability in QP, show that QP is semantically incomplete, and invalidate the widespread claim that contextuality is unavoidable in QP. Furthermore. SR introduces some changes in the conventional interpretation of ideal measurements and Heisenbergs uncertainty principle.     

Electron-transfer oxidation of dioxenes. An example of radical cation disproportionation

Tris(p-bromophenyl ammoniumyl) tetrafluoroborate induces an easy electron-transfer process on dioxenes leading quantitatively to the corresponding α-diketones. A mechanism involving the disproportionation of the intermediate radical cations is discussed.     

Dramatically enhanced carbon acidity of the nitrobenzyl fragment in a nickel(II) scorpionate complex

The -CH(2)- group of the 2-nitrobenzyl pendant arm of the scorpionate complex I deprotonates in basic aqueous solution (pK(a) = 10.6), due to the coordination of the nitronate group to the nickel(II) center. Metal coordination enhances 2-nitrobenzene acidity by 10 orders of magnitude. [reaction: see text]     

Transition metal complexes with bidentate ligands spanning trans-positions. VI. The preparation of some diaryl- and dialkyl derivatives of 2,11-bis (phosphinomethyl)benzo [c]phenanthrene

The preparation of the ditertiary phosphines 2,11-bis (di-m-tolylphosphinomethyl)benzo [c]phenanthrene ( 1b ), 2,11-bis (di-p-anisylphosphinomethyl)benzo-[c]phenanthrene ( 1c ), 2,11-bis (di-m-trifluoromethylphenylphosphinomethyl) benzo-[c]phenanthrene ( 1d ), 2,11-bis (dicyclohexylphosphinomethyl)benzo [c]phenanthrene ( 1e ) and 2,11-bis [di-(t-butyl)phosphinomethyl]benzo [c]phenanthrene ( 1f ), by a combination of synthetic routes is described.     

RuO4-catalyzed oxidative polycyclization of squalene. Determination of the configuration of the penta-tetrahydrofuranyl diol product

The configuration of the penta-tetrahydrofuranyl diol (penta-THF) product obtained by a single-step, RuO₄-catalyzed oxidative polycyclization of squalene, has been determined as cis-threo-cis-threo-trans-threo-trans-threo-trans. The cis-cis-trans-trans-trans sequence for the five contiguous THF rings has been established through extensive 2D-NMR spectroscopic studies carried out both on the intact molecule and on some of its derivatives, including the oxidative cleavage products obtained by degradation of the penta-THF with PCC/AcOH. Four different chemical approaches were devised to determine each of the four threo relationships within each carbon pair connecting adjacent THF rings in the molecule. To this aim, studies have been carried out either on some intermediates of the process leading to penta-THF, obtained by stopping the oxidation of squalene prior to completion, or on a degradation product of the penta-THF, obtained from the latter through a bidirectional double oxidative degradation with PCC.     

Potentiometric determination of boron in graphite microspheres for nuclear engineering

The well-known acidimetric determination of boron via the boric acid-mannitol complex is applied to the analysis of boron-loaded graphite microspheres used in nuclear engineering. After the sample is accurately ground, it is fused with an oxidizing alkaline flux. The melt is dissolved with warm water, the solution is acidified to completely remove carbon dioxide and the boric acid is titrated potentiometrically with carbonate-free sodium hydroxide after its complexing with mannitol.The determination of at least 0.2% boron in graphite is carried out with an average error of less than 1%.     

Oligosaccharides Related to Tumor-Associate Antigens. Part 4. Modeling of the terminal tetrasaccharide of an antigen recognized by the MBr1 antibody and of overlapping Di- and trisaccharide sequences

The conformational space of the tetrasaccharide α-L -Fuc-(1→2)-β-D -Gal-(1→3)-β-D -GalNAc-(1→3)-α-D -GallPr ( 3 ) and of some overlapping di- and trisaccharide sequences was investigated with the aid of molecular-mechanics energy minimizations, molecular-dynamics simulations, and ¹H-NMR analysis. These investigations suggested that in compound 3 a certain rigidity of the first two glycosidic linkages (Fuc-Gal and Gal-GalNAc) is combined with the flexibility of the third one (GalNAc-Gal).